The Cyprus Institute

About: The Cyprus Institute is a other organization based out in Nicosia, Cyprus. It is known for research contribution in the topics: Aerosol & Environmental science. The organization has 418 authors who have published 1252 publications receiving 32586 citations.

Optimizing Regional Climate Model Output for Hydro-Climate Applications in the Eastern Nile Basin

Abstract: This study focuses on the Eastern Nile (EN) Basin, most of whose water flows into the High Aswan Dam (HAD), Egypt. It is, therefore, crucial to have an accurate hydrological assessment overtime to plan water resource management in the area. With complex topography, it is important to capture most of the physics captured with the least bias in meteorological information. Weather Research and Forecasting (WRF) model was configured for a nested domain centered over the EN basin with a parent domain defined over the larger Middle East–North Africa (MENA) region at 0.09 degrees and 0.44 degrees spatial resolution, respectively. The bias correction of the model is performed with associated meteorological parameters. WRF physics parameterization sensitivity experiments were carried out to select an optimum combination of physics schemes. The model skill was also examined by downscaling the ERA-Interim reanalysis dataset from 1980 to 2009 over the EN basin domain. The WRF performance was assessed using gridded observational datasets for precipitation and temperature output. The results revealed significant positive precipitation bias, especially over the highlands. The bias-corrected precipitation data is coupled to the semi-distributed hydrological rainfall-runoff—Soil and Water Assessment Tool (SWAT)—model, previously configured for the Baro-Akobo-Sobat sub-basin. The simulated flow hydrograph based on bias-corrected WRF simulations enhanced high correlations and Nash–Sutcliffe Efficiency coefficients (from 0.61 to 0.79) for the observed flow hydrographs, hence improved hydrologic simulations. Results indicated that the bias-corrected precipitation fields from WRF can contribute to improved hydrological impact assessments.

Observed rainfall trends and precipitation uncertainty in the vicinity of the Mediterranean, Middle East and North Africa

Abstract: The present study investigates the century-long and more recent rainfall trends over the greater region of Middle East and North Africa (MENA). Five up-to-date gridded observational datasets are employed. Besides mean annual values, trends of six indices of drought and extreme precipitation are also considered in the analysis. Most important findings include the significant negative trends over the Maghreb, Levant, Arabian Peninsula, and Sahel regions that are evident since the beginning of the twentieth century and are more or less extended to today. On the other hand, for some Mediterranean regions such as the Balkans and the Anatolian Plateau, precipitation records during the most recent decades indicate a significant increasing trend and a recovering from the dry conditions that occurred during the mid-1970s and mid-1980s. The fact that over parts of the study region the selected datasets were found to have substantial differences in terms of mean climate, trends, and interannual variability, motivated the more thorough investigation of the precipitation observational uncertainty. Several aspects, such as annual and monthly mean climatologies and also discrepancies in the monthly time-series distribution, are discussed using common methods in the field of climatology but also more sophisticated, nonparametric approaches such as the Kruskal–Wallis and Dunn’s tests. Results indicate that in the best case, the data sources are found to have statistically significant differences in the distribution of monthly precipitation for about 50% of the study region extent. This percentage is increased up to 70% when particular datasets are compared. Indicatively, the range between the tested rainfall datasets is found to be more than 20% of their mean annual values for most of the extent of MENA, while locally, for the hyper-arid regions, this percentage is increased up to 100%. Precipitation observational uncertainty is also profound for parts of southern Europe. Outlier datasets over individual regions are identified in order to be more cautiously used in future regional climate studies.

Hidden graffiti identification on marble surfaces through photogrammetry and remote sensing techniques

Abstract: . Nowadays, considering the various methodological approaches used by the scientific community to study graffiti, there is a need for the improvement of the documentation and analysis workflow that must be addressed. Historic graffiti are recognized by scholars of different disciplines as a relevant and genuine written source, able to provide an insight into the everyday life of the past. Many studies have indeed flourished during the last decades stating the relevance of graffiti as a multidisciplinary source of information and showing, at the same time, the fragmented research scenario due to the lack of reliable and standardized methodologies. Currently, the scientific community involved in the study of graffiti has largely benefited from the use of digital technologies. However, most of the efforts and research projects were focused on the analysis of graffiti immediately visible on the surface or graffiti the position of which was easily identifiable due to the depth and width of the engraving. The proposed study is intended to tackle the documentation pipeline a step earlier than the documentation itself when the graffiti are yet to be identified. The San Marco Basilica in Venice is used as a unique case study for the analysis of non-directly visible-to-human-eye graffiti in a rather challenging environment.

Aerosol water parameterization: long-term evaluation and importance

Abstract: . We scrutinize the importance of aerosol water for the aerosol optical depth (AOD) calculations by a long-term evaluation of the EQuilibrium Simplified Aerosol Model V4 for climate modeling, which was introduced by Metzger et al. (2016a). EQSAM4clim is based on a sin-gle solute coefficient approach that efficiently parameterizes hygroscopic growth, account- ing for aerosol water uptake from the deliquescence relative humidity up to supersaturation. EQSAM4clim extends the single solute coefficient approach to treat water uptake of multi- component mixtures. The gas-aerosol partitioning and the mixed solution water uptake can be solved analytically, preventing the need for iterations, which is computationally efficient. EQSAM4clim has been implemented in the global chemistry climate model EMAC and com- pared to ISORROPIA II (Fountoukis and Nenes, 2007) at climate time-scales. Our global modeling results show that (I) our EMAC results of the aerosol optical depth (AOD) are comparable to independent results of Pozzer et al. (2015) for the period 2000–2010, (II) the results of various aerosol properties of EQSAM4clim and ISORROPIA II are similar and in agreement with AERONET and EMEP observations for the period 2000–2013, and (III) that the underlying assumptions on the aerosol water uptake limitations are important for derived AOD calculations. Sensitivity studies of different levels of chemical aging and associated water uptake show larger effects on AOD calculations for the year 2005 compared to the differences associated with the application of the two gas-liquid-solid partitioning schemes. Altogether, our study reveals the importance of the aerosol water for climate applications.

Representing gazetteers and period thesauri in four-dimensional space---time

Abstract: Gazetteers, i.e., lists of place-names, enable having a global vision of places of interest through the assignment of a point, or a region, to a place name. However, such identification of the location corresponding to a place name is often a difficult task. There is no one-to-one correspondence between the two sets, places and names, because of name variants, different names for the same place and homonymy; the location corresponding to a place name may vary in time, changing its extension or even the position; and, in general, there is the imprecision deriving from the association of a concept belonging to language (the place name) to a precise concept (the spatial location). Also for named time periods, e.g., early Bronze Age, which are of current use in archaeology, the situation is similar: they depend on the location to which they refer as the same period may have different time-spans in different locations. The present paper avails of a recent extension of the CIDOC CRM called CRMgeo, which embeds events in a spatio-temporal 4-dimensional framework. The paper uses concepts from CRMgeo and introduces extensions to model gazetteers and period thesauri. This approach enables dealing with time-varying location appellations as well as with space-varying period appellations on a robust basis. For this purpose a refinement/extension of CRMgeo is proposed and a discretization of space and time is used to approximate real space---time extents occupied by events. Such an approach solves the problem and suggests further investigations in various directions.